Art of producing continuous sheet glass



Oct. 13, 1925-.

` 1,556,665 c. w. AVERY lEr Al. ART OF-PRODUCINGIGVONTINUOUS SHEET GLASS :5 Sheets-Sheet 1 Filed April 1;, 1922 A Sme/lou lART OF PRODUGING CONTINUOUS SHEET GLASS Filed April 13, 1922v 3 Sheets-Sheet 2 mefwtou UCI/eye@ Wye/y, Edward jrOa/,

attouwgd Oct. 13, 1925- 1,556,665 .v c. w. AVERYETAL.

ART DF- PRODUCING CONTINUOUS SHEET GLASS Filed April 13, 19.22l s. vsheets-swat s Edward .7,7

.Patented '-113,71925. i I i. 'l I 1 UNITED `s'rfkrlazsl 1PnrE`1aT`l orpi-Cn! CLARENCE w. AVERY AND EDWARD' T. snows, or nE'rnoI'I, MICHIGAN, AssIeNons ro'ronn )moron ConrANY, or DETROIT, MICHIGAN, A ConronA'rIoN or DELA- WARE. v

` ABT or rnonUCING CONTINUOUS snnnrCILAss. e l i Aptncan'op med April 1aL 1922. 'i semi no. 552,095. i

To all 'tvhom it may concern; u substantially fifty per cen-tum (one-eighth 55 Be it known that we, CLARENCE W. AVERY. inch) on each side, thus b n into the and.A EnwAnn T. BROWN, citizens of the factor of' cost of production o \t e finished United- States, residing atf Detroit, in" the sheet not only the quantity of molten glass 5 county ,of Wayne and State of Michigan, employed, but also the time and labor fac- 'have invented certain newl and useful Imtor involved in removingthis' excess quan- .60 provements in the Art of Produci Contity.

tinuous Sheet Glass, of which the fol owing Jlfonts have been made to producel the. is specifica/Lion, continuous sheet b frollingbetween rolls 10. This invention relates to improvements 1n using a substantia y vertical sheet pass in' the art of producing sheet 'glass in continuthe rolls but such structures introduce the 65 ouslengths, pertaining more particularly factor of the production of sheets having characterislivered mto a p'ool atthe throat of the ticsof the plate glass type. pass-and thus tend to set up a more or less i Glass sheets of the plate glass typeforced arrangement of particles or molecules sheets having a finished thickness, for in-` 0f the molten metal, due to the neceity of 70 stance of one-fourth, inch-are enerally employlng confining walls to the pool and produced by the casting. process, in that the constantly-added supply on the upper the molten glass or metal is dumped on to surface of the pool producing the weight or V ar flat table and then rolled to' a size of exgravity factor which tends to produce this cess thickness, 4after which the sheet is suborced arrangement of the component parts 75 jected to a grinding 'and polishing action to of the' mass passing into and through the produce the finished transparent plate. To pass. produce plates of any niaterial size in sur- Many other ways have. been vattem ed, face dimension, ther-table must be of correthose .referred to vbeing thus descri n `befspondingly large sizeit is generally as causeof the emphasis these Vplace 'to the 80 `large as can be conveniently securedy and characteristics lof. the t invention employedthus exposing a large surface to' which pertains more particularly to the sothe sheet material during the casting period. lution of the problems involved by the use Sheets formed in this way are generally cast of the casting method type of operation extra heavy in thickness-the sheet which rather than thel drawing method, in that the 954 produces the one-fourth inch finished plate characteristics of a pool are employed, but is cast with a thickness of one-half inchthe l, as well as the pa, are of uncondue tothe fact that the expansion and con-A in characteristic. l ltraction effect, together with other inherent For the purpose of indicating the general characteristics, tend .to set. up conditions characteristics of the present invention, 'a 9 0` which may be orare similar to the condibrief staaemefnt is made of one of, its emtions of warping at points on the table; bodiments that is in service andpnoducing these conditions are more or less 'inherent continuous sheets which, as the lsheet 40 and cannot be controlled'definitely, the reeiner Afrom'the leerA is cut into the proper sul-t being that the sheet niust have an inilen'gtss and then subjected tothe 9.5

tial thickness such as will permit grinding-4 and polishrin action to produce the off of 'sufficient amount of the sheet surfaces product. T e installation produces linto eliminate the faults set -up becauseofl ls'hed sheets yofoneourth inch thickness, 4t these inherent conditions. As will be unthe sheet, howeveffbeing formed of a'thick- Y v del-stood, the larger the dimensions of the, ness of tlu'ee-eighth inch-as compared tn mo sheet the greater .becomes the diiliculty` the one-.half inch of the usual casting procferred-to.' b ess -thus setting up a saving'pf 25% in the, Asa result of these conditions it becomes amount of material, employed in -the roevident thatfwith `the one-fourth. nchfin-IO' duction of sheets of equal length andwldth ished' product,A for `instance, the molten, ais/'between the installation and the usual M glass-requredto. produce' it substancastingprocess, and a savingvin the time y'tially 'l double that found the finished and labor in the grindingand liShng, due

product, this excess being then ground ofL-f .to the fact .that .only 50% Ao thev sheet .is

gravity-if the metal is first dea ness, and its width l is substantially twentywasted by grinding and polishin as compared with the 100% amounlt oft e'casting process, the percentages being on the basis of the thickness of the finished product, the waste in the usual cast-ing process bein equal in thickness to that of thel final pro 4 uct. u

In the installation referred to the melting and refining chamber have a capacity of approximately sixteen tons of molten metal every 24 hours, the discharge spout having an active width of flowing metal of approximately eight inches. The melting, chamber is charged with the raw materials a-t regular intervals and inf` amounts such as to maintain the content between approximate and minimum amount limits.

The leer is in excess of four hundred and fifty feet in length, and its entrance is spaced less than ten feetthe distance is about five and a half feet-from the discharge end of the spout from the refining chamber. The leer supports the sheet on rollers, positively driven at speeds such as to prevent any piling up of the sheet within the leer under normaloperation, the rollers being arranged in series of units with the unit spacing differing in a gradually increasing distance. ratio.

The sheet is three-eighth inch in thickfive inches. l The sheet advances at the rate of approximately twenty-eight inches per 'minute At the outer end of the leer the sheet is cut into regular lelgths, the product being employed in the pr uction of windshield sections, etc.; the cut lengths are'then 'subjected to' a grinding and pollshing action which leaves them one-fourth linch thick, the lossin thickness bein one-eighth inch (50%) in thickness' in t e grinding and polishing action, the lengths being ground and polished on both faces.

The portion of the installation that bears more particularl on the present invention is that between t e discharge spout and the entrance to the leer, the ortion of the apparatus within the few eet between these parts, It is here that the 'sheet is formed.V y The table is in-the form of an endless ele- .ment made up of connected sections having a horizontal flight of a length greater than the distance between the leer and the point of discharge from the spout, the excess length extending beneath the spout; this permits of the table formation being complete-in advance of reaching the oint where the discharging metal is recelved. The table forms the lower wall of the ass, the upper wall being formed by a roller supported above the table, the roller being approximately thirteen inches in diameter, the spacing being three-eighth inch. Both roller and table are of greater width than the width of the sheet. For purpose of smoothing out any slight inaccuracies in the upper surface, an additional roller is located beyond the forming roller-between ,the latter and the leer. The table has its upper surface approximately six inches below the lip of the discharge spout, and the table and roller are driven at synchronousequal-speeds.

' The molten metalfrom the spout passes downward on to the table by gravity and is advanced to the pass to be formed into the sheet and then advanced intothe leer.- As

will be understood, the horizontal table surpasses on to the uppe-r surface of the pool and in flowing maintains'the general dimensions of the pool. The amount of metal within the pool a pears to be possiblyone or one and ahal times the uantity that would be contained in an ordinary water pail. j

The discharge spout is dis osed midway of the length of the roller an width off-the table, so that the'contour of the poolis symmetrical, having a width at the point of entrance of the stream a little greater than the width of the stream, 'the width increasing symmetrically on opposite sides as it approaches the pass. .The constancy ofthe pool Vdimensions is made apparent to the observer through the fact that the table sur- :faceJ appears to be moving steadily forward beneath the lpool with the latter appearing to remain stationary; in other words, the.

to the table and then permittedto flow gently and nonforcibl into its approximate sheetl formation, t e mouth lof the pass serving torestrain forward movement of the during motion of the'table, lformed an increased thickness of pool as the mouth is approached and reached, thus slightly increasing the effect of gravity and entire pool so that there is.

Aprovided for the molten Vbeing such as to unconned pool to ticles of the metal arrange themselves in.

a natural way relative'to each other, the

.treatment not forcing any particular and definite arrangement, but permitting a free and natural How of the metal.

The result. is brought about by the fact that no restraint is appliedv to the flow. The pass is of greater'width thanrthesheet sov that the edges of the sheet are 4not-confined, and no laterally confining walls are metal in advance of the pass, the consistency of the metal provide for flowing action but with uniformity. It is the lack of any confiningv walls of. any vkind that distinguishes the pool of the present invention `from the usual meaning of the word pool,; the contentl is that. which would be found within a depression, but the entire content is above the .plane of the top of thel table, so that the entire surface 'of the pool content, excepting.

is wholly lunconfined, thus freedom .of flow laterally, the pass is reached, all

of the roller, permitting entire the flow endingp as parts "being of equal thickness. of a better term, we have givenl the term designate this content.

As will be understood, the consistency of the molten glass or metal is of importance in this connection. The temperature within the spout is approximately 2100"' F.,

' appear rounded 'while that of the metal forming the pool is approximately 19800 at the point where the streamenters the-pool, the additional drop in reaching the pass being comparatively small so that the material has that degree will permit flow at a substantially uniform rat; suitable burners are arranged surface Aof the pool in order to prevent chilling of the surface.' The consistency is such, therefore, as will permit lateral flow without thinning out of the lateral edge' contour of the pool to a point where l1t would be of less thickness thanthe Adepth of the pass, the contour being such as to in a cross-section of .the pool; this effect is made manifest in the pass where the'I edges of the sheet are found to be rounded, the rolled sheet having this ."round edge characteristic, indicating that the flow at no time reaches the knife-blade edge stage.

The distance from the pass to Jthe/point of, entrance of the stream into the. pool. is approximatelyfifteen inches, and it 1s during the travel of this distance that this free llateral flow takes place; the heel of the pool extends beyond this point of entrance, so that 4the metalrfof the pool is in contact Y advancing,

that in contact with thev table topand that in contact with the face For want relative to the exposed;

-Flow of metal downwardly ytablelateral ow is -contact is had.

'the lateral flow -with the table ,fora greater distance than this fifteen inches; the reasonv for this rounded edge appearance is probably to be found in the fact that the "zone of contact of metal and. table at'the heel of the pool is of practically fixed dimensions and is so that the owing metal is over' the material of this zone laterally as it ad-l vances, thus adding to the edges with the vad'ded parts brought into contact with a clean portion of the tablethus increasmg the zone of-contact, the length of travel of the table being timed so that,l theilow lproducesl .a final width approximating; uniformityof width of the sheet.

It is obvious, ofcourse, that the consistency of the metal varies substantially constantly as is the case with molten glass being supplied in this manner, and with cons'tant .speed conditions in the table and roller, these variations aect the width o f Ythe sheet. This can'be and isV met by a control system for regulating the speed of `the table and roller and that of the supports in the leer, as for.` instance by the use of a rheostat control of the' motors which operate these, either manually or automatically; A if manual, an attendant measures the sheet width at frequent intervals, changing the speed in presence of variations from a normal width; and this control can be-.obtained by a suitable detector with which the sheet edgesjcooperate, and'which, through variations in width, will automatically varyl the motor speed to compensate for changes in consistency. In the installation referred to, sheet width may lvary7 within a fraction of an inch when operating under'manual con-v trol, but remains practically constant under the automatic control, the detector being positioned in to permitA change in speed in immediate succession to `the change in consistency becoming manifest in the pass..

Another of the characteristics of the invention will be understood fromthe above. under the action of gravity such as to present conditions of pressure is practically restricted to' the stream flow from the discharge spout, and v this flow is not resisted. The length of such iow, however, is such rassure values on the material in the pool' eel, .so that the pool is not disturbed by this constant supply, the pressure being suficient,however, 'to cause the lategal flow to begin at once and thus maintain the condi'- tions of the molten metal bed on to which thestreamis owing, thus preventing immediate contact of the stream with the required Since poolis in the brought about bythe change indepth of the pool toward the roller-'- close proximity to the pass as to set upmaterial Xiao before 'such v all movement ofthe horizontal plane-excepting gravitation has no material effect on the metal to force it into unnatural flow conditions.

Another characteristic is found inthe fact that while. the pool varies in depth, the increase-is upwardly, wi-th the increase in the saine plane,

to the plane of thegbottom face of the sheet during its travel as a sheet.4v Hence, there accompanying drawings,

.Y the is no change in direction of travel of the metal after it reaches the pool, such as might tend vto set up conditions of strain in the sheet.

.Other characteristics are present and will v,be referred to hereinafter.

To these and other ends, nature of which'WilLbe readily understood as the invention is hereinafter more fully disclosed, said invention consists in the improved methods and arrangements and combinations of arts and structures,v hereinafter more ful y described, illustrated in the and more particu-l larly pointed'out in the'appended claims.

In the accompanying drawings, in which similar reference characters indicate similar parts in each of the views- Figure 1 is a sectional View, partly in elevation, showing portions'of a system designed for carrying out the general embodiments of the present invention.

Fig. 2 is a plan view showing parts of apparatus employed in the system of 1g. 1.

Fig. 3 is a transverse sectional view taken through the table with the section extending -through the pool.V

Fig. 4 is a detail sectional View showing the pass.

Fig. 5 is'a detail'sectional view looking toward the supply stream, the section extending transverse ofthe pool.

Fig. 6 'is a diagrammatic view showing va, form of drive for the table.

Fig. 7 is a diagrammatic view indicating a method for con-trolling the speed to compensate for changes in consistency.

For the purpose of illustrating the invention, the drawingshave the' general characteristics of the installation to which reference hasJ been made, the details of construction, etc., however, being omitted and therefore, the

many sho'wn in simplified form, it being understood, of course, that eachinstallation of the invention will ca its own det-ail structural characteristicsnd'esigned to meet the individual conditions ofthe installation, and will be designed more particularly to meet these conditions. The drawings, Vtherefore, are not to lbe'considered as more than illustrative of the invention.

The meltingand rehning tankis indicated at A, and shown as provlded with the dis Aof the-molten metal from the tank;

.of one unit sp .out p tus is -indicated generally at C in wheels 19 and 19,

imacat charge spout the latter being :rovid-ed with a gate aafor .controlling the discharge two of thesegates are shown in order to provide 'a reserve gate formation. It willl be under` thatA these parts are of any stood, ofcourse, preferred construction and arran ement designed to provide a continuous ow o f the molten metal in a generally regulated amount.

B indicates the leer of suitable construction and lengthQ'tlie leer carrying a. suitable sheet-advancing arrau ement, shownyas in the form of rolls b suitably supported and positively driven. 'In practice, rolls b have been arranged in sets or units with the rolls an increased distance over those of another unit, as indicated in Fig. 7, for instance, the increase being toward the discharge end of the leer. To drive the' rolls one or more motor-driven shafts b lmay be employed, each roll having an operative connection with theshaftas by a worm-drive arrangement, for instancethe arrangement being such as to bring about conditions in which the sheet is pro erly advanced through the leer withacing any material dra-wing strain on the sheet and without tending to set up conditions that would cause the sheet to become piledup within the leer.V A single shaft may drive all of the rolls, with the shaft 0perated by a motor b2, but it is preferred to employ a plurality of shafts and motors 'with the latter synchronized in such manner as to setup the desired speed condi- Y tions Within the units.

The sheet .forming portion-of the alpparawherein is shown a simplitedarrangement for carrying out the invention. I'This p0rtion consists generally of a table o and a roller o', the table being in the form of an endless member having a horizontal Hight that serves the function of the table and abovewhich is positioned roller'c vto produce therebetween the conditions of a pass c2. Y

15 indicates a frame carrying shafts \16 and 17, shatlG being driven by a motor 18,'shaft 17 being driven from shaft Y16. Shafts 16 and 17 are provided with sprocket respectively, over which are trained ak pair like formations 20, these making up an endless-chain arrangement which is also trained over an idle shaft 2 and its sprocket wheels 21. v

The rlinks which form the chain`20 are adapted to carry individual plates 22 of' a length such as the table o, the

of complementa] chainsents the top plane ofthe table; this produces a different' effect atthe opposite end of the flight-shown at'ltheleft of Fig. 1-but this is immaterial because the plates must move a considerable distance in the flight a,

:v be^fore receiving the molten metal.

As will be understood, the fact that shaft 16 is the drive shaft for the .endless-chain table formation tends to vset up the condi- `tions of a' push action within the horizontal ight w,' in other words, instead of the table being advanced by drawing or pulling the plates in the direction of flight at, the

plates 'are advanced by being pushed from vthe rear, the result being that the table top is maintained free from joint Aopenings along the longitudinal meeting edges of adjacent plates. To prevent conditions of buckling in such surface, the structure is arranged to also set up. an adva'ncin action by drive of shaft 17 but the drive ofthe latter shaft is had from shaft 16, with the drive connections arranged' to set up conditions of compensation a simplified arrange` ment being shown in VFig. 6. A

This compensated drive is, provided by` lthe use\of a sprocket chain l'connection between the shafts independent of the endless i ,table formation, the chain being indicated at 24. To support chain 24, shaft 16 carries a loose sprocket formation 25, and shaft 17 carriesa xedfsprocket 26, chain 24 being trainedv on these sprockets 25 and 26.

y "Sprocket 25 is driven by a drive member 25a keyed or otherwise secured to yshaft 16, element 25a being located' in a recess of sprocket 25;r a springV 25b beingy interposed between the element and sprocket, the arrangement being such that advance of shaft 16 causes similar advance .of the element 25a and the mbtio'n of the latter is communicated to sprocket 25 through spring 25"; the resultant'movement of clain 24 drives shaft 17 through sprocket 26. As shown in Figs.l 1

- and 6^the sprockets of shaft 16 are of different size from those of sl1a'ftv17, and the sprockets of the two chain systems differ from but the 'arrangement is such that the same relationf between the number of teeth ven Hthe sprockets is main-,g

'i tained in both'chain systems.' Forinstance, with sprockets 1 9 carrying ten teeth and sprocket i sprockets 19"" sevenl teeth, the number of teethofsproeket 25 willbe ten and that of 26 will be seven. This provides for 'adefinite drive relation between the two/ i lshasfts 16 and 17, spring 25b setting u'p the comiwnsans. action/active te prevent pull- `2 about the stream.

ing Istrains `or buckling inthe horizontal flight ar.

As shown in Fig. 2, roller o is .driven produce a pass of proper characteristic.'

Roller c is preferably ofthe water-cooled type, and table is also preferablyzwater- `cooled, Fig. 1 illustrating, at 27, a suitable spraying instrumentality suppliedv vfrom a suitable source of supply, not shown.

It is, of course, impossible to presentan exact delineation vof the configuration or appearance of the pool of metal fromwhich the sheet is formed. In the drawings this has been approximated to a certain extent, and `indicated at p, the downowing or gravity stream being indicated at p.

As will be understood, stream p is of an entirely different cross-sectional contour fr0m that of the sheet, the, width of the stream approximating thirty per centum of the Widthof the sheet, while the stream thicknessl is correspondmgly thicker than the sheet; the one .characteristic in common between the sheet and stream is the fact that the contentper unit of'length of the stream'will equal the content of the sheet in the same unit of length-in other Words, the vsupply of metal provided by the, stream balances. the amount of metal leaving the pool in the form of the sheet formation.

Both table c and roller c are moving continuously in an advancing direction, so that the pool, content is Vbeing constantly advanced toward the pass; and while there is this constant advance of the metal there is also a constant addition in the form of the stream content -which is flowing on to the top of the pool and spreadin out laterally so as to roduce the heel e ect shown in Fig. 1 an the'mat-like effect shown in Fig.

'It ris obvious, of course, that lthere is,

time .factor present between the instant of joining the andthe instant when the content reac es the pass, and durin this time interval the molten metal will te dto How laterally. If the table were stationary, there would be* a adual' thinning of the pool thickness as t e metal flow 'wouldKincrease the area of `contact with the table.`

But owing to the lfact `that the'table is cony' stantly moving,

characteristic 1s being adde constantly, a

section transverse of the pool will present av substantially constant cross-sectional con' though this lateral flow of metal tour, even continues;.due tothe fact'that the advancf in 'crQss-sect'ion is being replaced by a simi lar y-produc'ed crpss-section of metal, And

this is' made possible .by thelfactthatthe- ,and a .sup ly of similar, f

, pool increases in contour dimensions of the stream vary very leaving a considerable open flow-zone on' eachside without passing outside of the desired sheet width.

Since the advance of toward the mouth presente by lthe curved face of the rollerand the strai ht face of theA table, it will be understood t at there is set up a resistance to advance of the upper Vportion of the pool the result being that the depth toward the mouth, the increase', however, being in an upward a direction, so that the metal must flow downward throu h a greater distance and hence more vrapidy as the thickness increases. And yet,the flow is the natural lw of the metal resisted only in the directionof ad- Vance by the form of themouth to the pass as set upby the curvature of roller c'-are sistance that produces this characteristic of an increasing depth to the pool and which tends to direct t e flow laterally to obtain the desired sheet width. I

As heretofore pointed out,@the arrangement sets u -the conditions of an unconned pool o the metaLthe content' of the pool Vbeing advanced by a pushing action rather. than being drawn, it being readily understood that the yaction of the table is 'that of simply carrying the content forward, the last added increment of the metal being added to the pool at the rear ofA the latter and in such manner as to not materially disturb the pool content. l

If desired, although such arran ement is not compulsory, a roller 30 may mountedin the path of# travel of the formed sheet, intermediate roller c and the entrance to the leer, roller 30 being used for the purpose of smoothing out any slight irregularlties that might appear on the upper surface of` the sheet, the roller being adjustable ver tically to providethe proper width of pass between it and the table,

One ofthe characteristics that has beenl .manifested by the use of the invention is that the falling stream does not act to produce strains or nerate bubbles, etc. Occasional' bubbles ave .been noted, but these werenoted during travel of the metal in the spout and were not broken up by the fallin stream action, It was possible to note t e course of these bubbles in traversing the pool and it i'sfound that these generally ap ear at or adjacent an edge of the sheet, a ubble of this kind serving as an excellent indicator vto note the characteristics of the metal flow in traversing 4the pool,

this demonstrating, the freedom of such now. It has been found that there is no trapping of air action producedby the stream in joinin the ool, and the fact that bubbles within e st are mantnedin pool content is l width p necessar the l is indicative of the fact of no materia disturbance of the metal of the stream and pool by reasonof the gravitating lflow of metal in the stream.

The particular shape of the pool may vary in use by reason of variation in the consistency ofthe molten metal. The heel may vary in-projection, depending on such consistency, as may other portions of the pool. Since it is-desired to maintain the sheet practically constant, it is essential that this variation be compensated as far as possible. This can be done by varying the speed of traLvel of the table and roller c', through var` lng the speed of the motor which drives s aft 1 6, and .such variation -should also extend to the rolls the the leer so`that'the latter will advance the sheet at the proper s eed to prevent i1ing up or a thinnmgo the sheet throng a tendency to draw. n

This control can be provided by a suitable controlling rheostat 31 as indicated in Fig. 7,`this device providing similar eiect on each of the driving motors involved. Regulation of the rheostat may be manualthe attendant making frequentinspection of the sheet to determine variations in sheet width, and shifting the rheostat to vary the I speed when necessary; obviously, a suitable detector may be applied beyond the forming pass, this detector being arranged to operate or control the changes in the rheostat, the variations being controlled 'by variation in thewidth of the sheet.

The surface-of the pool is maintained at proper temperature' by the vuse of one or more burners 32 properly positionedA with respect to the pool. In practice these are shiftable in position toaid in permitting manipulation toward maintaining` a proper consistency to the metal of the pool.

yWhile we have herein disclosed one .or more ways in which the lfundamental characteristics of the present invention may be carried out, together with an embodiment of apparatus adapted to practice the invention, it will be readily understood that variations or modifications thereof may be found desirable or essential in meeting the various exigencies of installation and of use, and

we desire to be understood as reserving the right to make any and all such changes and modifications as may be found 'desirable or in sofar as the same may fall within t e in the accompanying claims when roadl construed.

Having t us described our invention, what we claim-as new is:

1. In the art of producing continuous sheet glass, the method of forming the sheet which consists in establishing an unconined pool of the molten metal on a flat travcling surfacem advaucefof and leading to a irit and scope of tle invention through the pass to form the sheet',

forming -pass with'theass dimensions substantially equal to the t ickness of the sheet and rater than the width of the sheet, and contmually passing met-al from the pool whereb the unconined characteristic of the pool wi l be maintained within the pass with respect to'the sheet edges, the pool characteristic' bemg maintained by eling surface inv advance of and leading to a v forming pass,

the bottom of-the pool extending o n a horizontal plane, the pass `di mensionsl being such as to produce the approximate sheet thickness and preserve the .unconfinedN characteristic of the pool with respect to the-sheet edges, and forming the sheet by continually passlng metal romthe I of metal to the pool,

, lsheetglass,

pool through the pass while maintaining the pool characteristic by la continuous supply the width of the sheet being produced by the natural flow of met-al withm the pool. v

3. In the art of producing continuous the method of forming the sheet which consists in establishing an unconned plane of the bottom through the pass, the

tion and pool of the molten metal on a Hat traveling surface Iin advance of and leading to a'forming pass, the bottom of the pool extending on a horizontal plane` which represents the surface of the glass sheet, the pass dimensions being such as to produce the approximate sheet thickness and preservethe unconfined characteristic of the pool within the pass with respect to the sheet edges, and forming the sheet by continually passing metal from the 'pool through the pass while maintaining the pool characteristic by metal to the pool, the Width of the sheet bef ing produced by the naturalflow of metal Within the pool.

4. In thel art of producing continuous sheet glass, the method of forming thesheet which consists in establishing an advancing and unconfined pool content of the molten p metal on a liat traveling surface in advance of and leading to a forming pass, forming the sheet by passing metal of the pool through the pass, and maintaining the poslamount of metal in the pool by supplying molten metal to the pool concurrently with the forming of the sheet and 1n amount equal to that pass dimensions maintaining the unconfined characteristic with t to the sheet'edges, whereby the width of the sheet will be produced by the natural flow of the metal within th pool.

Vvin g pass, the pool having a continuous Vsupply of.

leaving the pool 5. In the, art of producing continuous sheet glass,the method of forming the sheet which consists in establishing an unconined pool of the molten metal on a flat traveling surface in advance of and leading to a formdefinite external contour configuration, forming the sheet` by passing metal -from the pool through the pass,l and approximately maintaining the constancy of the configura- 'lol an approximate tion during sheetform'ation by advancingy the pool content toward the -pass'gcon'currently with the addition of molten met-al to the pool equal 1n amount to-that passing through the'pas's, the unconned characteristic extending into the pass.

6.' In theart of 'producing continuous sheet glass, the method-of forming the sheet whichconsists in establishing an unconfined pool of the molten-metal on a flat traveling surface in 4advance of and leading to a fornithe pool having a width character increasing in the direction of ing pass, istie generally the pass with greatest width within the pass,

forming the sheet by passing metal from the pool through the pass,

and maintaining the width characteristic substantially -constant A during`- sheet -formation bly advancing the ool content toward the pass concurrently with the addition of molten metal to the vpool equal in amount to that passing through the pass while controlling the time length of travel -of the lool content between the point of metal addltion to the pool and the pass, the unconined characteristic; of the metal extending into the pass.

7. In the art' of producing -continuous;

sheet glass, the method of forming `the sheet which consists in establishing an unconfined qol of the molten-metal in'advance of. and leading to a forming pass, the pool having a width characteristic generally increasing in the direction of the Width within the`pass, forming the sheet by pass, and maintaining the width characteristic substantially constant during sheet forf,nationfby advancing equal in amount to that passing through the ass while 'controlling the time length fof travel ofthe pool'content between the point of metal addition to 'thepool and the pass,` the unconlined characteristic of' the inet-al extending into the pass.

pass with the greatest passing metal from the pool through 1the *111 the pool content hori- 'zontally towardv the pass concurrently with -the addition ofmolten metal to the pool 8. In the art vof producingl continuous sheet glass, the method of forming the sheet which consists in establishing an unconfined pool of the molten metal in `advance of an leading to a forming its bottom extending plane and having a depth characterlstic the direction of the pass, forming the sheet by passing metal from the pool pass, the pool having on a Single horizontal 'Y passing metal pass, and maintaining the depth character I travel of the the pam and above such bottom. of the 55 vhorizontal plane, the metal for through the pass, and maintaining the depth characteristic substantially constant durmg sheet formation by advancing the pool content horizontally toward the ass concurrently with the addition of mo ten metal to the pool equal in amount to that passing through the pass while controlling the time `length of travel of the pool content between generally increasing in the direction of the mouth of the pass, forming the sheet by from the pool through the istie substantially constant during sheet formation by advancing the pool content horizontally towardl the pass concurrently with the addition of molten metal'tothe'pool equal in amount to that passing through the pass while controlling the time length of of metal addltion to the poolv and the pass. 10. In the art of producin continuous sheet glass, the method of formm the sheet which consists in establishing a orizontally-advancin uncontined pool content of molten meta in advance of and leadin lto a ,forming pass,` the ,metal for the pool sing supplied by a vertically-flowing streamo the metal entering the pool remote from the pass, formingy the sheet by `passingmetal from the pool through the passz the approximate thickness 'of the sheet bemgproduced by dimensions of the pass and the width of the sheet being produced by natural flow of the metal in the pooI during advance of the pool content to the sheet-thickness-determining portion of the pass. Y `I 11. In the art of producing continuous sheet glass, the Jmethod of forming the sheet which consists .in establishing a horizontally-advancing unconfined pool content of molten metal in advance of and leading to a forming pass, forming the sheet by passing metal Vfrom the pool through the pass, the pool extending on Ia single the pool being supplied `by a vertically-flowing stream of the metal entering the pool remote from i horizontal plane, forming thesheet bypassing metal from the poolv throu h the pass, the approximate thickness o 'the sheet being produced b di mensions of the pass and the Width o the and of the under surface pool content between the point sheet glass, the metho s advancing unconined pass, the Width of the metal in advance of and'leading to a form-r ing pass, the bottomfof` the pool extending on a single horizontal' plane corrcsllonding With the' plane of the bottom of t e pass the metal for the pool being supplied by a vertically-owing stream of the metal entering the pool remote from the pass with thelike characteristic on to which the stream` passes in entering the pool, forming the of theformed sheet,

sheet by passing metal from the pool through the pass, 4the approximate thickness of the sheet being produced y dimensions of the pass and the width o the sheet 'beingproduced-by natural flow of the metal 1n the pass above such 'lane during advance of the pool content to t e sheet-thickness-determining portion of the ass.

13. In the art of ro ucing continuous sheet glass, the metho v of forming the sheet which consists in establishing a horizontally- 'advancing unconlined pool content of molten metal in advance of and leading to a forming'iass, the metal for the pool beingv su plle by a vertically-flowing stream of the metal entering the pool remote from the pass, the width of the stream being materially less than the width of the sheet and disposed substantially symmetrical t a line corresponding toa median line of the sheet, forming the sheet by passing metal from the ool through the pass, the approximate thic ess of the sheet being produced by action of the pass, and the width of the sheet being produced by natural flow of the metal in the pool during advance of the pool content to the sheet-thickness-determining por tion of the pases.

14. In the art of oducin continuous of forming the sheet which consists in establishing a horizontallypool content ofmolten metalv in advance of and leading to a forming pass, the metal for the pliedby a vertically-flowing"stream of y,t e metal entering the -pool remote from ythe stream being materialless than the. width of the sheet and disposed substantially symmetrical to a line corresponding to a median line of the/sheet,

formingthe sheet by passinggnetal from the pool through the pass e approximate thickness of the sheet being produced by pool Y being sulpaction othe pass and the width of the'sheet serving as tent to the sheet-thicknessdetermining portion of the pass, such natural How being generally symmetrical to vsuch line.

15. Inv the art of producing [continuous sheet glass, the method of forming the sheet which consists in establishing a horizontally-y advancing unconlined pool content ofmolten metal on a Hat traveling surface in advance 7 of and leading to a forming pass, forming the sheet by passing metal from the pool through the pass, maintaining an approximately constant value of metal within the pool by supplying molten metal to the pool during sheet formation and in amount equal to that passing from the. pool,

and controlling the width of the sheet by the speed of advance of the pool content to `the Hight extending in a horizontal plane and forming the lower wallof the pass, and an upper wall for .the pass, said formation thevsupport for the pool content to and through the pass and for the formed sheet in advance of entrance to the leer.'

17. Means as in claim 16 characterized in 'that tlieupper wall of the pass is provided by a rotating roller, the roller and table formation being operatively connected to provide equal surface-advancing speeds.

18. Means as in`claim -16 characterized in that the upper wall of the pass is provided by a rotating roller having a peripheral speed equal to the advancing speed of the table formation, the roller and table formation being active to produce a pass of greater length in the direction of roller axis than .l the width of the sheet being formed, there-v by maintaining the unconfined characteristic `of the pool within the pass with respect to the width dimension of thesheet.

19. Means as in claim 1,6 characterized in that the table formation includes an endless succession of plates of relatively narrow dimension in the direction of formation. advance and with the horizontal Hight including a number of such plates guided to travel in such plane, the guiding means having a length to position the'plates in such plane in advance of reaching the point of metal supply and beyond the pass station with p the plates maintained in edge contact. 1

20.- Means as in claim: 16 characterized in 'that the table vforma-tion includes an endless succession of plates movable in the planeof support such horizontal Hight in the direction of ad' l Avance of the pool, the power for advancing -tlie plates being appliedV at a point to cause each plate to be active in advancing the` 'i plates in advance of it on the flight, whereby the table formation will be advanced by a pushing action. l

21. Means as in claim l16 characterized in that the table formation includes an endless succession of ,plates movable in the plane ofv such horizontal Hight in the 'direction o'f advance of the pool, the power for advancing the plates being applied at a point to cause each plate to be active` in advancing the plates in advance of .it in they Hight, whereby'the tableformation -wil1.be advanced by a" pushing action, means being provided to prevent' buckling of the formation while active as the support for the pooland sheet.

22. Means as in claim 16 characterized in that the upper wall of the pass is provided',

by a rotating roller driven lin synchronism with the table-formation to produce equal speed characteristics to the up erand lower walls of the pass, and an ad itional rollerv operative upon the formed sheet while the sheet is supported by the'iftable formation to produce the finished upper-surface characteristie'to the formed sheet.

23. In combination with a melting furnace having a spout for discharging molten glass, and a leer, of means ,interposed between the spout and the Jleer for establishing an unf confined pool of the molten metal in advance of and leading to the forming pass with the pool supplied by the `metal from the spout and with the pool content continually advanced horizontally to carry it to, into and through the pass, said means including an advancing support for the metal of tliepool operative as the lower wall of the pass, and

a roller forming the up er'wall of the pass and driven synchronous y withthe sup ort, and means for controlling thewidth o the sheet by controllin the advancing speed of the support and ro ler.-

24. A' combination as in claim 23 charac'- "tei'ized in that the controlling means is active in the control of the speedof travel of the sheet within the leer. v

25, In the art of producing continuous sheet glass, a source of supply for the molten f metal, said source including a permanently positioned discharge spout, an advancing the molten metalfrom the spout to produce an unconfined pool'upon said support, said support being positioned to advance the pool content in av horizontal plane toward, into,

and beyond a forming pass of which the supthe spout being spaced above the support ort forms the lower wall, a rotating rollery assv located below thespout to receive 120 and the pool thereon a distance sufficient to pass being such as to permit natural `flow ofv provide a gravity How of metal from the the metal in the pool during travel of the spout to the pool, the active width of the pool content toward and into the pass. 1W

spout being materially less than the width of vIn testimony whereof we alix our signa-5 5 the sheet vto produce a supply stream of metal tures.

of less Width than the sheet, the distance be- CLARENCE W. AVERY.

tween the supply stream and `the forming EDWARD .T. BROWN. 

